Automatic transmission



June 3, 1952 E. E. WEMP 2,599,215

AUTOMATIC TRANSMISSION Filed Oct. 18, 1950 17 Sheets-Sheet l INVENTOR. Emea/ t'. IMP/77,0

June 3, 1952 E. E. WEMP 2,599,215

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AUTOMATIC TRANSMISSION Filed Oct. 18, 1950 17 Sheets-Sheet 5 INVENTOR. fr'nasf E. Wemp Wau A 7' TORNE VS June 3, 1952 E. E. WEMP 2,599,215

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AUTOMATIC TRANSMISSION Filed Oct. 18, 1950 17 Sheets-Sheet 9 INVENTOR. Ernesf E. Wem o A TTOENEYS June 3, 1952 E. E. WEMP 2,599,215

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E. E. WEMP 2,599,215

AUTOMATIC TRANSMISSION Oct. 18, 1950 17 Sheets-Sheet l7 F IEnEE.

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Ernesf f. Wemp 2 Q i i :6 l6 1e 10 PISTON 772AvE1. -INcHE$ Patented June 3, 1952 AUTOMATIC TRANSMISSION jErnest ,Wemp, Detroit, Mich, assignor, by ,direct and mesne assignments, of sixty-five per cent to himself, five per cent to Clyde '3. Smith, five percent to Leah Kathleen Smith; twenty -percent to Lila Ar Wemp, all of Detroit, Mich, and' fivexper centte Eleanor May Wemp, Los

. Apnlicationfictsoher 18, 1950, Serial No.;190',807

application iserial ';No.";77-3,2.48, filed *September 1 10, 1947,-now, abandoned.

.The;principa1 objects-f the invention are 'to provide an improved .itransmission construction and control therefor "by means of which several speedmatiosgare obtainedin-an automatic mannerthrough whichthe'torque of the engine is transmitted --to *theifinal outputgmember which is"co,upled"totthewheelspf thevehicle. To this end, a transmission "construction is provided which, in itselfifprovides a positive'driving action in theiowspiced-ratio, which is the one usually employed when the vehicle-is started from a standing position, and the-transmission is arrangedtonbe employed in "combination with a coupling to the engine 70f "an automatic nature. The-"coupling is'one which-will permitthe engine to --operate at an idling speed, while the vehicle stands g-at rest but which, "upon acceleration of the engine,-transmits torque to'the transmission.

One-formofsuchnoupling is a fluid coupling commonly known *as the fluid flywheel. The invention is disclosediii-conjunction with a fluid flywheel. Such "aicoupling, While having a slippingaction when "the engine is idling and the J vehicle is attrest, nevertheless transmits some torque which *tends to cause the vehicle to creep. -It-is an object of the invention to provide a transmission which, while otherwise normally conditioned to transmit torque to the traction wheels -uponjaoceleration of the engine, eliminates the-creeping action by means which overcomes the relatively small amount of torque which causes the "creeping action.

More particularlyythe invention provides an a-utomatictransmission comprised of two sections-sorelated as to be capableof providing four speedratios. One'section preferablyem'codies a planetary gear set with automatic control means whereby the planetary'gear-set may be locked up to iunctionas a unit or conditioned to transmit torque through the operating gears. Another section, which may be for convenience, termed therange selector section, is in the nature of a gear-box'soarrangedthat torque may be transtittedth-rough-the gears andso thatdriving and driven -parts "may be coupled together in dental engagement "for transmitting torque directly thereth-rough. Withthe two sections properly relatediourspeeds are obtainableand hydraulic means are provided-under the dual control of 15 Claims. (Cl. 7464'5) speed and torque for selectively conditioning the transmission for cheating the proper speed ratio. The transmissionalso is so constructed as to provide for transmitting the torque in reverse and so that the vehicle may be pushed ortowed to start the engine.

A construction in accordance with the invention is disclosed in the accompanyingdrawings:

Fig. 1 is a side elevational view of the transmission housing.

Fig. -2 is a side elevational viewofthe opposite side of the-transmission"housingillustrating the connectionto a throttle control.

Fig. 3 is a general view, largely incross-section, of "a transmission constructed in accordance with the invention, illustrating the same together with a fluid coupling situated between the engine andthe transmission.

Fig; 3a is an enlarged cross sectional view of the forward part of the transmission.

Fig. 4 is --a sectional view-slightly enlarged relative to Fig. 3, taken substantiallyon "line 4--4;of Figs. 3 and 3a, illustrating controlling elements for the planetary gear set.

Fig-'5 is a view, slightlyenlarged 1'elative to Fig.3, takensubstantially on line 55 of Figs. 3 and 3a, illustrating elements of the planetary gear set an'dsome-o'f-the controllingmechanism.

. Fig. 6 is a slightly enlarged view taken substantiallyonline (5-45 of Fig.3 illustratingelements in-the rear or range selector section of the transmission.

Fig. isa slightly-enlarged sectional view taken substantially on line 1-1 of Fig. 3 showing blocking mechanism and-control mechanism in the range selector section of the transmission.

Fig. -8 is anenlarged view partly in section showing the pump structure for the hydraulic medium and showing some control mechanism.

Fig. 9-is an enlarged developed-view in cross section showing the-range selector-section of the transmission.

Fig. 9a is across sectional "view of the coupler operating means illustrated in Fig. 9 showing the parts in position about tomake-a-range shift.

Fig-9b is a sectional view similarto "Fig. 9a showing the coupler operating -mechanism "and the coupler in shifted'position.

Fig. 9c isa view similar-to Figs.-'9a and 9b-sh-owing the coupler operating means in a position about t'o-shift the coupler to-theposition shown clutch arrangement in the planetary gear set of the transmission.

Fig. 11 is an enlarged view taken substantially on line of Fig. 3 showing the face view of block structure for controlling the action of dentally engaging teeth. in the range selector section and showing some parts in section.

Fig. 12 is an enlarged sectional view taken substantially on line |2|2 of Fig. 3 showing some of the blocking elements in the range selector section.

Fig. 13 is a developed sectional view illustrating the disengaged position of dentally engaging teeth and showing elements of the blocker structure.

Fig. 13a is a view similar to Fig. 13 showing the blocker elements in blocked position.

Fig. 135 is a view similar to Figs. 13 and 13a showing the teeth in dental engagement.

Fig. 14 is an inside face view of a cover plate for the housing which incorporates hydraulic controlling means.

Fig. 15 is a view illustrating diagrammatically the hydraulic system and showing the structure of controlling valve mechanism, the view illustrating the condition of the hydraulic system in first or low speed; the hydraulic medium being introduced into those parts and conduits shown by the dark lines.

Fig. 16 is a view similar to Fig. 15 showing the condition of the hydraulic system in second speed.

Fig. 17 is a diagrammatic view similar to Fig. 15 showing the condition of the hydraulic system in third speed.

Fig. 18 is a diagrammatic view similar to Fig. 15 showing the condition of the hydraulic system in fourth speed.

Fig. 19 is a diagrammatic View similar to Fig. 15 showing the condition of the hydraulic system in the overcontrol position.

Fig. 20 is a diagrammatic view similar to Fig.

15 illustrating the function of the system in a power shift from third speed to second speedn Fig. 21 is a diagrammatic view showing the relationship of the spring rates of the mechanism 7:

for actuating the coupler in the range selector section.

Fig. 22 is a diagram demonstrating pattern shifts of the transmission.

As illustrated in Figs. 1 and 2, the transmission includes a front housing and a rear housing 2, the front housing being arranged to be connected to the block of an engine by means of cap screws 3. The flywheel of the engine is illustrated at 4 (Fig. 3) and it carries the impeller 5 of a fluid coupling, commonly termed a fluid flywheel, the runner of the coupling being illustrated at 6. The running is keyed or splined as at to an element which may be termed a drive shaft 8, inasmuch as the element 8 is the power input member for the transmission. The impeller and runner are provided with a fluid seal as shown at 9.

The drive shaft 8, which, for the most part, is in the form of a sleeve, is journalled in the housingl preferably through the means of an antifriction bearing l2, which, in turn, is situated in a bearing member |3 disposed in a hub-like portion l4 in the housing. The forward end of shaft 8 is piloted in a bearing l5 which also serves to pilot the hub of the runner. The drive element 8 has an enlarged sleeve portion l1 and has a further enlarged portion l8 and it terminates in a flange I9. Cooperating with flange I9 is an element having a flange 23 and a hub portion 2 I.

Flange l9 and the cooperating element 20 con- 7 stitute the carrier for the pinions of-a planetary gear set. One pinion 23 is shown in Fig. 3, journalled upon a hollow pin 24, the ends of which are carried respectively by the flange l9 and the flange 20. Advantageously three of Such pinions 23 are provided, as shown in Fig. 5, each preferably journalled on its pin by anti-friction roller bearing 24.

An internal ring gear '26 has its teeth meshing with those of the pinions 23. This ring gear 26 is non-rotatably mounted upon a flange element 21 which has a hub portion 28 keyed as at 29 to a shaft 30. The shaft 30 telescopes within the section of the drive element 8 and may be piloted by a bearing 32 and it is journalled as at 33 in a partition plate 34 located between the two housings of the transmission.

The sun gear of the planetary gear set is shown at 35 and it has an extending part 33 which is keyed to the hub portion 38 of a member 4!).

Situated between the member 40 and the hub portion 2| of the carrier 23 is a friction clutch. To this end, the member 40 has an extending part 4| and an end plate 42 so as to carry bolts 44, upon which a series of clutch discs 45 are mounted (Fig. 4) while alternate clutch discs 46 are mounted on the hub portion 2|. The extension 4| has extending fingers 43 interlocked with the end plate 42 as shown in Fig. 10.

The member 43 is constructed so as to constitute a cylinder formation in which is disposed a piston 48 which acts upon the pack of clutch discs 45, 45, when, as will later be seen, liquid under pressure is introduced into the cylindrical chamber 49. As will be seen by reference to Fig. 4, coil springs 50 are alternately positioned relative to the :bolts 44. These coil springs act upon the piston 48 and upon the end plate 42 so as to normally retract the piston in order to free the clutch plates 45, 46 relative to each other.

There is an overrunning clutch arrangement between the sun gear and the planet carrier. Specifically, this lies between the extension 36 of the sun gear and a portion of the hub 2|. The rollers of the overrunning clutch are illustrated at 53 (Fig. 3 and Fig. 10). A roller retainer 55 is acted upon by a coil spring 56 so that they are held, or urged in a clockwise direction as Fig. 10 is viewed. The rollers function upon an inner circular surface 58 of the carrier member 2| and upon flat surface portions 5! of the sun gear.

Considering Fig. 10 for the moment, the normal direction of rotation of the elements is counterclockwise as indicated by the arrows. It will be at once appreciated that the carrier member 2| may overrun, that is, run faster than, the sun gear and its portion 36, but that the moment the carrier member 2| tends to rotate slower than the gear, that is, by relative rotation which would be clockwise relative to the sun gear, the rollers 53 the brake band normally released and the piston in the head portion of the cylinder. The brake band is applicable to the portion 4 Thus, when the brake band is applied the sun gear is held stationary; the connection between the member 4| and the sun gear, tracing back through the memers and parts 49, 38, 36 and to the sun gear 35.

There is also a control for the carrier as illustrated in Fig. 5, this being in the form of a brake band 19 anchored as at II and acted on by two opposing springs 72 and 73 which react oppositely on a finger portion I4 of the brake band. A piston 75 in a cylinder 16 acts upon a rod 1'! which has a washer I8 which provides the reaction for springs I3. In the normal running position of the parts, hydraulic liquid under pressure enters the cylinder I5, pushes the piston to the position shown in Fig. so that the brake band I9 is released. When the pressure of the liquid is inadequate as, for example, when the vehicle comes to a stop, and the engine is idling, the hydraulic pressure ceases or drops permitting the piston to back away against the action of the spring I2 and the brake band 19 is then applied to the flange T9 of an element which is connected to the carrier.

The purpose of this is as follows: If the engine is operating at an idling speed and there is no desire to transmit torque to the traction wheels of the vehicle, there is, nevertheless, a residual torque transmitted through the fluid coupling. In other words, the impeller 5 is rotating with the engine and while there is considerable slippage of the fluid coupling at such relatively low speed of rotation, torque is nevertheless placed on the runner 6 which, of course, is transmitted to the carrier. The brake band I9 grips the element 19 and thus holds the carrier from turning incident to this torque. As will be explained later, as soon as the engine is accelerated, liquid under pressure is pumped into the cylinder 16 to release the brake member. The brake III has substantially only a sufiicient torque capacity to overcome the creeping action.

Before proceeding with the remaining description, it might be well to briefly consider the operation of the planetary gear set without, however, going into full detail of the automatic functions of the control of the transmission. It has just been pointed out how, with the engine idling, the torque transmitted by the fluid coupling is overcome by the brake band I9, but this is released in the normal operation of the construction. If the carrier and the sun gear are locked together as a unit, they revolve about the axis of the transmis- Y sion but the pinions 23 do not rotate on their own axes and, therefore, the ring gear rotates in unison with the carrier and the sun gear. This drives the member 39 at a 1:1 ratio relative to the engine, except, of course, for the expected slippage I in the fluid coupling. There is, in any event, a 1:1 ratio between the runner 6 and the member 39. If the sun gear is held against rotation and the carrier is released from its locked engagement with the sun gear, then, considering Fig. 5, the carrier revolves counterclockwise about the axis, the pinions rotate on their axes and the ring gear is driven at a speed of rotation faster than the carrier. Therefore, the member 39 is rotating faster than the engine, disregarding again any slippage in the fluid coupling. Thus, the planetary gear set is capable of providing two speed ratios as between the engine and the torque transmitting member 39.

The range selector section of the transmission in the rear housing 2 can probably be best appreciated by reference to the developed view of Fig. 9. This section is arranged to transmit torque directly at a 1:1 speed ratio and to transmit torque through gearing at a lower speed ratio.

6 The member 30has a gear portion and a flange 9| with an extending sleeve 92 provided with an end plate 93. A series of clutch discs 94 are slidably mounted internally in the extension 92. Alternate clutch plates are slidably mounted on a hub element 96 which is connected by means of splines or the like 98 to an output shaft 99. The shaft 99 is arranged to receive a coupling element I09 for connection to a shaft extending to the traction wheels of the vehicle. The flange 9| and extension 92 constitute a cylinder 9'! and in the cylinder is a piston I92 arranged to act upon the clutch plates to pack them together with the end plate 93 taking the reaction. The piston is normally held retracted by a number of springs I93 which react against a member I04 carried by a hub-like extension I05 of the member 39. The shaft 99 is piloted in the hub section I95 through roller bearings I06. It will be appreciated that if the piston is shifted to the r ght as 9 is viewed, the clutch plates 94, 95 are acked together and torque can be transmitted through the clutch plates, the hub element 96 and to the shaft 99 with a direct drive at 1:1 speed rati between the shaft 39 and the shaft 99.

The gearing includes a counter-shaft I i9, upon which is mounted a gear II I, the teeth of which mesh with those of gear 99 and the gear I II has a sleeve H2 upon which is slidably mounted a gear I I3 whose teeth may mesh with those of gear I I4 which is journalled as at I I5 on the shaft 99. As will be presently seen, the gear H4 may be coupled with the hub element 95 and thus the torque may be transmitted from member 39 through the gears described to the shaft 99 at a reduced speed ratio.

The range selector section also includes reverse gearing. This comprises a shaft H8 upon which is mounted a gear H9 whose teeth mesh with those of gear II I and which has a sleeve I29 with a slidably mounted gear I2I thereon. The shafts III! and H8 are on centers equidistant from the shaft 99 as wil be seen by reference to Fig. 6, but the gear H9, being smaller than gear III, has a clearance with respect to gear 99 and if torque is transmitted through gear H9 and I2I, the gear I I4 is rotated in a reverse direction with the teeth of gear IZIVmeshing with those of gear I I4.

The gears H3 and I2I are arranged so that only one may be in engagement with gear I I4 at a time. In Fig. 9 the gear II 3 is positioned to drive gear II 4 while the gear I2I is shifted out of position. When a reverse is to be made, the gear H3 is shifted to its dotted line position and the gear I2I is shifted to its dotted line position, in which position it drives the gear H4.

For selectively shifting the gears H3 and I2I, there is a lever I23 mounted on a sleeve I 24 which carries an arm I25 having a. shoe I26 in engagement with a flange on the gear II 3 (Fig. 9). Another arm or lever I2! is on a rod I28 having an arm I29 with a shoe I39 in engagement with the gear IZI (Fig. 9). The arms I25 and I29 are interlocked by means of oppositely disposed detents I33 and I34 carried by a bracket member I35 and pressed outwardly by a spring I39. The detents engage respectively in the recesses in the arms I25 and I 29. Only when one of the gears H3 or I2I is disengaged from the gear H4 can the other of the gears H3 or I2I be shifted into engagement with gear I I4. This is because, for example, the detent I33 must be seated in its cooperating recess and arm I29 in order to provide for adequate retraction of detent I34 for movement of the arm I25. Likewise, the detent 

